Under the current relay system, an assistant acts as an intermediary to convert speech to text and vice versa for the two parties.

Ofcom's research found that callers were frustrated by the inability to interrupt, have “real time” conversations or express emotion.

The speed of conversation is generally slow, as callers must take turns to speak or type.

The new service, which will be in place within 18 months, will include a range of new features, including parallel two-way speech, which makes use of an internet connection to allow users to interject, instead of having to wait until the end of a message; and a wider range of equipment for accessing the service, including easier use of text relay on the move via mobile phones.

Ofcom is also exploring the impact of speech recognition technology on the accuracy and speeds of current and future relay services.

It is also working to encourage the provision of video relay services.